Thoracic re-irradiation with SBRT for residual/recurrent and new primary NSCLC within or immediately adjacent to a prior high-dose radiation field

Publication date: Available online 8 December 2017
Source:Practical Radiation Oncology
Author(s): Zachary D. Horne, Michael J. Dohopolski, David A. Clump, Steven A. Burton, Dwight E. Heron
PurposeLocal failure following concurrent chemoradiation, as well as in-lobe failures following SBRT are common. We evaluated our institutional experience using stereotactic body radiation therapy (SBRT) as salvage in this setting.Materials and MethodsSeventy-two patients were re-irradiated with SBRT for residual, locally recurrent, or new primary non-small cell lung cancer (NSCLC) within or adjacent to a high-dose EBRT or SBRT field. Kaplan–Meier with log-rank test were used to estimate endpoints and differentiate cohorts.ResultsMedian follow-up was 17.9months. Patients had residual or recurrent disease (54.2%) and 45.8% had new lung primaries. Median re-irradiated T-size was 2.5cm (range: 0.8–7.8cm). Median pre-retreatment SUVmax was 7.15 (range: 1.2–37.6). The most common SBRT re-irradiation regimen was 48Gy in 4 fractions (range: 17-60Gy in 1–5 fractions).Median progression-free survival was 15.2months and median overall survival was 20.8months. Two-year local failure was 21.6%. Patients with SUVmax at re-irradiation below 7.0 had a 2-year local control of 93.1% versus 61.1% above the median (p<0.001). The 2-year rate of distant metastases was 10.4% versus 54.1% in patients treated for a new primary versus residual or recurrent disease (p<0.001). Median progression-free survival was 31.9months versus 8.4months, respectively (p=0.037).Median survival of patients treated for new primary was 25.2months versus 16.2months with residual or recurrent disease (p=0.049) and median survival for patients with re-irradiation SUVmax below the median was 42.0months versus 9.8months above the median (p<0.001). Acute any grade toxicity was seen in 29.2% of patients, acute grade 3 toxicity in 11.1%, and late grade 3 toxicity in 1.4% with no treatment-related deaths.ConclusionsSBRT appears to be a safe and effective means of salvaging recurrent, residual, or new primary NSCLC in or adjacent to a previous high-dose radiation field.



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